Comparison of digital dental X-ray systems with self-developing film and manual processing for endodontic file length determination

Comparison of Digital Radiography, Conventional Film and Self-Developing Film for Working Length Determination

INTRODUCTION

Accurate measurement of working length of the root canal is an important factor in endodontic treatment, because it determines the level of cleaning and shaping of the canal. This can be performed using numerous methods including conventional, digital and self-developing methods, which are studied in this work.

METHODS AND MATERIALS

In this study, 50 maxillary molars with appropriate conditions for the analysis were collected and their mesiobuccal canal lengths were estimated by three different types of radiographs with and without file. Next, two endodontists and a radiologist reviewed all the images under the same conditions. The precise lengths of the canals were measured by removing teeth from their casts and direct observation. Finally, data regarding differences in radiographic length and actual length were examined by SPSS 16.0 software and Repeated Measures ANOVA test.

RESULTS

There was no significant difference in any of the radiographic states. The differences of root canal lengths were not significant for the first (endodontist) and third (endodontist) observers; whereas, there were significant differences for the second observer (radiologist). The differences were not significant for samples without files (P=0.89). However, the differences were significant for samples with files (P=0.03).

CONCLUSION

Since analysis showed that there were no significant differences between the results of digital radiography, conventional film and self-developing film methods in working length determination, the clinician can choose any of these methods according to the working conditions without being concerned about losing the accuracy.

Root canal treatment and special needs patients

AIM

To identify current trends of root canal treatment for patients with special needs.

METHODOLOGY

A postal questionnaire was sent to General Dentists in Victoria, Australia and Endodontists and Special Needs Dentists across Australia to determine the extent of root canal treatment performed on special needs patients.

RESULTS

Over a four-month period, 1120 questionnaires were distributed with an overall response rate of 63.9% (n = 716). Response rates were 63.2% (n = 655), 68.5% (n = 50) and 100.0% (n = 11) amongst General Dentists, Endodontists and Special Needs Dentists, respectively. Endodontists (95.7%) and Special Needs Dentists (100.0%) performed significantly more root canal treatment on adult patients with special needs compared with 51.2% of General Dentists, (P < 0.001 and P = 0.001 respectively; Fisher's exact test). The most common reasons for not undertaking root canal treatment included limited cooperation, poor oral hygiene and uncontrolled movement. Amongst General Dentists, 75.7% opted for extraction in preference to root canal treatment. Significantly, more specialist practitioners performed root canal treatment utilizing conscious sedation (P < 0.001) and general anaesthesia (P = 0.003). Most specialist practitioners (69.1%) had undertaken single-visit root canal treatment on special needs patients compared with only 29.7% of General Dentists (P < 0.001).

CONCLUSIONS

Root canal treatment in special needs patients was more likely to be carried out by specialist dental practitioners who were more likely to utilize a pharmacological approach for behaviour guidance and to perform single-visit root canal treatment compared with General Dentists. A multidisciplinary approach for special needs patients who require root canal treatment provides an opportunity for these patients to retain their dentition.

Perceived quality, clarity, and accuracy of manually processed and self-developing radiographs in endodontics

OBJECTIVES

To evaluate perceived quality, clarity, and accuracy of self-developing films compared to conventional D- and E-speed manually processed films, and to evaluate their ease of use and satisfaction amongst pre-clinical dental students.

METHODOLOGY

Mesiobuccal root canals of 30 extracted mandibular molar teeth were instrumented and size 10 K-files were glued into the canals at 3 different levels. Each tooth was exposed thrice with the same angulation using conventional E-speed, D-speed, and self-developing films. Conventional films were processed manually and self-developing films according to the manufacturer's instructions, which required 50 seconds of contact time with the solution. Radiographs were evaluated by 4 examiners for quality, clarity, and apical position of the file. A questionnaire-based survey was conducted to evaluate the ease of use, quality, and satisfaction of undergraduate students. Data were analyzed using one-way ANOVA and Tukey-Kramer multiple comparison test, significant at p < 0.05.

RESULTS

The quality and clarity of conventional E-speed films was perceived as significantly better than that of D-speed and self-developing films (p < 0.05). There was no statistically significant difference amongst the 3 film types for recorded file positions (p > 0.05). The results of the student survey corroborated the examiners' views that the self-developing radiographic films were of poor quality.

CONCLUSION

Manually processed E-speed films provided significantly superior quality and clarity of images, but for apical file position, no significant differences were found amongst the 3 film types. Conventional E-speed, D-speed, and self-developing films are all adequate for measuring endodontic working lengths.

Comparison of working length determination using apex locator, conventional radiography and radiovisiography: an in vitro study

AIM

The purpose of this study was to compare the working length determination done using three methods, namely, apex locator (Foramatron D-10, Parkell), radiovisiography (Planmeca) and conventional radiography (Prostyle intra, Planmeca).

MATERIALS AND METHODS

In this experiment, to determine the working length, 35 single-rooted teeth were selected and each tooth was subjected to all the three methods of the working length determination. This was compared with the actual working length measured utilizing ground sections of the individual teeth.

RESULTS

The results revealed that all the three methods located the apex nearly as accurately as the actual root canal length obtained by histological ground sectioning, and among three methods apex locator being the closest to the actual root canal length.

CONCLUSION

The study concludes that all the three techniques are equally effective in determining working length.

Digital analysis of mouthrinses? staining characteristics on provisional acrylic resins

Provisional restorations are expected to be both aestethically and physically durable during the preparation of permanent restorations. In this study, the staining properties of mouthrinses containing chlorhexidine gluconate, benzydamine hydrochloride and a hybrid mouthrinse were investigated on light and dark shades of a provisional acrylic resin. Totally 80 specimens were prepared and were photographed digitally to obtain the baseline L*, a*, b* values. Each sample was immersed in test solutions for 12 h which was equivalent time to 1 year of mouthrinse use, and the post-treatment images of the test materials were acquired. All L*, a*, b* values were analysed by a graphic software, and the total colour change (DeltaE*) of each specimen was calculated. Also the same colour analyses were performed on all test solutions to establish their colour parameters. Analysis of variance and Tukey's tests were used for statistical analyses and alpha was 0.05. All test solutions produced perceptible staining on the provisional material, with DeltaE values over 3.7. In both shades, hybrid rinse caused the highest staining (DeltaE=5.705), and was followed by chlorhexidine gluconate rinse, with DeltaE value of 4.120. The third highest staining was observed with benzydamine hydrochloride rinse (DeltaE=3.959), whereas the control caused the least staining (DeltaE=3.095). The lighter shade provisional material resulted with clinically observable staining even when immersed in distilled water; however, the dark shades showed clinically perceptible staining solely with the hybrid mouthrinse. In this study, the shade of the acrylic material was the determinator of the staining process.

Digital and Advanced Imaging in Endodontics: A Review

This review provides an overview of digital radiography as it exists, including advanced imaging such as computed tomography (CT), cone beam volumetric imaging, and micro-CT as relevant to the practice of endodontics. An evidence-based approach to adoption of different imaging technologies is included to assist the practitioner with the selection process of imaging modalities. Commonly used imaging terminology is introduced, as well as the advantages and disadvantages of image processing. New image reconstruction techniques have been introduced that provide information three-dimensionally to the clinician for routine endodontic and surgical treatment planning. The age of three-dimensional imaging and image processing is here. Limitations and advantages of newly introduced imaging modalities are discussed briefly.

Effects of imaging system and exposure on accurate detection of the second mesio-buccal canal in maxillary molar teeth

OBJECTIVES

The objectives of this study were to determine observer ability to detect the second mesio-buccal canal (MB2) in maxillary molars using analog film, CMOS, and photostimulable phosphor x-ray detectors across a wide range of radiation exposures and to determine the optimal exposures for these modalities accurately detecting presence of the MB2.

RESEARCH DESIGN

Using 6 experimental models with 2 maxillary molars in each, images were generated with the 3 detector modalities at nominal x-ray beam angulations of 0 degrees and 10 degrees across a range of radiation exposures. Observers independently assessed presence of the MB2 in images presented in random order. Horizontal root sections were then evaluated to determine true MB2 presence.

RESULTS

For single images at optimal exposures, the correct number of mesiobuccal canals could be identified 55% of the time for CMOS (RVG 6000), 44% of the time for analog x-ray film (InSight), and 39% of the time for photostimulable phosphor (DenOptix). Statistically significant differences were observed between the imaging modalities (chi2 = 23.4, crucial value = 5.99, P < or = .05). RVG 6000 CMOS outperformed both DenOptix photostimulable phosphor (z score = -5.5) and InSight analog direct exposure x-ray film (z score = 4). Exposure affected the rate of accuracy for MB2 detection across the exposure range tested for RVG 6000 and for film, but not to any appreciable degree for DenOptix.

CONCLUSIONS

The CMOS detector (RVG-6000) performed best for evaluating presence of the MB2. This was the only modality to exceed 50% reliability with optimal exposure when single images were considered.

Effect of various digital processing algorithms on the measurement accuracy of endodontic file length

OBJECTIVE

The aim of this study was to compare the accuracy of endodontic file lengths after application of various image enhancement modalities.

STUDY DESIGN

Endodontic files of three different ISO sizes were inserted in 20 single-rooted extracted permanent mandibular premolar teeth and standardized images were obtained. Original digital images were then enhanced using five processing algorithms. Six evaluators measured the length of each file on each image. The measurements from each processing algorithm and each file size were compared using repeated measures ANOVA and Bonferroni tests (P = 0.05). Paired t test was performed to compare the measurements with the true lengths of the files (P = 0.05).

RESULTS

All of the processing algorithms provided significantly shorter measurements than the true length of each file size (P < 0.05). The threshold enhancement modality produced significantly higher mean error values (P < 0.05), while there was no significant difference among the other enhancement modalities (P > 0.05). Decrease in mean error value was observed with increasing file size (P < 0.05).

CONCLUSIONS

Invert, contrast/brightness and edge enhancement algorithms may be recommended for accurate file length measurements when utilizing storage phosphor plates.

Ex vivo comparison of digital images with conventional radiographs for detection of simulated voids in root canal filling material

AIM

To compare the diagnostic potential of direct digital images with conventional radiographs for the detection of simulated root canal voids.

METHODOLOGY

The root canals of 80 extracted maxillary incisors with straight root canals were prepared and filled and the specimens divided into two groups: (i) a group of 40 teeth without voids; and, (ii) a group of 40 teeth with voids created in the root filling. Each root was imaged using the paralleling technique with a CCD-based digital system and F-speed film. Totally, there were 240 images: conventional radiographs (n = 80), digital images (n = 80) and digital zoomed images at 2x magnification (n = 80). These were interpreted for voids by a radiologist (without prior knowledge of the distribution of the voids). The reliability of the radiologist was confirmed using Cohen's Kappa Statistic, with the kappa value found to be >0.08. The sensitivity, specificity and predictive values were calculated. The differences in sensitivity and specificity between the imaging systems were then assessed using the Exact McNemar significance probability at the 95% significance level.

RESULTS

The sensitivities (95% CI) of conventional radiographs, digital images and zoomed images were 0.68 (0.57-0.78), 0.83 (0.74-0.91) and 0.80 (0.71-0.89), respectively. The specificities of the conventional radiographs, digital and zoomed images were 0.80 (0.71-0.89), 0.83 (0.74-0.91) and 0.83 (0.74-0.91), respectively. The positive predictive values (95% CI) were 0.77 (0.68-0.86), 0.83 (0.74-0.91) and 0.82 (0.74-0.90), respectively. The negative predictive values (95% CI) were 0.71 (0.61-0.81), 0.83 (0.74-0.91) and 0.80 (0.72-0.89), respectively. There were no significant differences between the sensitivity and specificity of digital images and conventional radiographs, and of digital images and zoomed images during the detection of voids in root fillings (P > 0.05).

CONCLUSIONS

Under the conditions of this laboratory study, the diagnostic performance of digital images and conventional radiographs, and between the digital images and digital zoomed images for simulated void detection in root fillings were not significantly different.

Comparison of digital and spectrophotometric measurements of colour shade guides

Colour determination may be precisely performed with spectrophotometers, however this technique is time consuming and requires special devices. The aim of this study was to determine the correlation between the colour measurements performed on three shade guides of the same manufacturer, obtained with digital and spectrophotometric analyses. Sixty shade tabs of three shade guides were analysed to determine the L*, a*, b* values with a spectrophotometer. The same shade tabs were also imaged with a digital camera, and same colour parameters were determined on the digital images with the software. Three measurements for each shade tab were made with both methods. Statistical differences between the results of two methods were determined using anova (alpha = 0.05). Additionally, presence of any correlation between two methods within each guide was investigated by using correlation analysis. It was observed that the a* and b* values obtained by digital method were correlated with those of the spectrophotometer. Spectrophotometric analysis revealed no disparities among the L* measurements of the shade tabs of three shade guides (P > 0.05), but significant differences were observed between the L* values of the shade tabs with digital analysis method (P = 0.000). The digital method formed more subgroups than the spectrophotometer. For a* and b* values, both methods revealed significant differences among the shade tabs (P < 0.05). Additionally, both analyses revealed that colour characteristics of the first shade guide was different than the other two. The results obtained by digital method were correlated with those of the spectrophotometer, especially for a* and b* values.

A laboratory comparison of three imaging systems for image quality and radiation exposure characteristics

AIM

To measure and compare the relationships between image quality and X-ray exposure for three types of intraoral imaging system (conventional film, phosphor plate system and CCD-based system).

METHODOLOGY

Kodak 'Insight' F-speed film, Digora FMX (phosphor plate system) and Visualix USB (CCD system) were used to produce series of radiographic images of two tooth-bearing jaw specimens (maxillary molar and mandibular molar regions) at a range of X-ray exposures from 10 ms to 2000 ms (all at 6 mA and 60 kV). Digital images were viewed from a computer monitor and films viewed on a conventional light box. Five observers scored each image using a five-point subjective image quality scale (0-4).

RESULTS

Optimum image quality (4) was seen for conventional film. Neither digital system achieved this score at any exposure, achieving in both cases a maximum mean score of 3.1 (adequate visualization). The two digital systems, however, provided adequate visualization at substantially lower exposure times. Dose reduction over conventional film for maximum quality images with Visualix USB was 20%, but for Digora FMX it was 70%. All three systems gave acceptable (quality score of two or higher) images over a broad range of exposures.

CONCLUSIONS

In terms of subjective image quality, F-speed film performed better than the two digital systems, but this must be weighed against the ability of the two digital systems to give adequate image quality at lower radiation doses.

Comparative analysis of the visualization of small files using digital and conventional radiography

The present work was designed to carry out a comparative analysis of the visualization of small files using digital and conventional radiographs. Forty maxillary molars inserted in human skulls were used; Maillefer K-files #06, #08, #10 and #15 were inserted in the mesiobuccal canals and measured at 0.5mm beyond and 1.5mm before the tip with 0.5-mm intervals, in order to allow five professionals to observe whether the files were at the limit, before or beyond the foramen when visualized on conventional radiographs taken on Insight Kodak film (Eastman Kodak, Rochester, NY, USA) and with the RVG digital system (Trophy). Based on the results obtained, the conclusions were: with the two systems it was possible to visualize #06 K-files in nearly 60% of the evaluated cases; for the others, #08, #10 and #15 K-files, visualization was higher with both radiographic systems, achieving 82% of correct visualization for #15 K-files with the conventional system. The differences between the results of the two systems studied - conventional (Insight film, Kodak F-speed) and last generation digital (RVG - Trophy) radiographs - were not statistically significant according to the Student's t test.

Evaluation of the linear measurements by conventional radiographs and indirect digital images in the endodontic treatment

INTRODUCTION

A successful endodontic therapy depends on the linear measurements obtained by means of radiographs taken during odontometry and also on the application of the established working length up to the final obturation.

OBJECTIVE

The aim of this study was to compare the precision of the linear measurement obtained by means of conventional radiographs and indirect digital images evaluated by the Digora 1.5 software during the different stages of endodontic treatment, as well as to evaluate the tools available on this software.

METHODS

A total of 160 radiographs of single-rooted teeth were obtained from files, which were analysed and divided in 4 groups comprising odontometry, cone fit, condensation and the final obturation. Analyses of the conventional radiographs and digitized images were performed by five previuosly calibrated examiners.

RESULTS

A high level of inter and intra-examiner agreement was observed through application of the Kendall coefficient and the correlation index, respectively. In relation to the results of linear measurement, the two-way variance analyses and the Tukey test revealed that, concerning the method, a statistically significant decrease was observed on the measurement obtained through the digital method when compared to the conventional radiograph (p<0,05). Moreover, the measurement presented a statistically significant difference among the different stages of endodontic treatment. Regarding interpretation of the digitized image, there was a statistically significant preference towards the Brightness and Contrast tool of the Digora 1.5 software, as evaluated through the Friedman test.

CONCLUSION

The present study demonstrated that image processing by the digital method aids the radiographic interpretation and consequently the determination of reference points for the achievement of the small linear measurements of endodontic treatment. The digital image provided statistically significant smaller linear measurements than those obtained by the conventional method.

Evaluation of endodontic files in digital radiographs before and after employing three image processing algorithms

OBJECTIVES

Two digital image processing algorithms, one aimed at correction for exponential attenuation and one at correction for visual response, have been developed. The aims of the present study were to test whether digital radiographs processed with these algorithms improve determination of the length of endodontic files and whether such processed radiographs are comparable with the radiographs processed with a default image processing method employed by one commercially available digital intraoral system.

METHODS

A dried human skull embedded in an acrylic compound was used for exposing radiographs of the upper and lower premolars and molars with endodontic files (Kerr files size 10 and size 15) positioned to the full length of the roots or 1.5 mm short of it. Radiographs were then processed in three sets. In one set, the radiographs were processed to compensate for exponential attenuation and the response of the human visual system. In the second, the radiographs were processed with the same compensation but with an additional shift in grey levels so that the output luminance in dentin at root tips corresponds to the mean of the luminance range of a computer monitor. In the third, the radiographs were processed with the default processing method in the Sidexis program. Ten viewers evaluated all radiographs. Receiver operating characteristic (ROC) curves were obtained and areas under the curves were calculated.

RESULTS

For file size 10, ROC curves for processed radiographs were higher than that for originals, while for file size 15, ROC curves for processed and original radiographs were close to each other. Significant differences were found between processed and original radiographs regarding areas under ROC curves for file size 10 but not between the differently processed radiographs. For file size 15, no significant differences were found.

CONCLUSION

Radiographs processed to correct for attenuation and visual response may improve determination of the length of thin endodontic files. Such processed radiographs are comparable with the radiographs processed with the default processing method in the Sidexis program.

Comparison of direct digital and conventional intraoral radiographs in detecting alveolar bone loss

BACKGROUND

Intraoral radiographs are important diagnostic aids in periodontics. The authors conducted a study to compare estimates of bone levels from direct digital and conventional radiographic under normal clinical use.

METHODS

A full-mouth series of conventional radiographs was taken for each of 25 subjects who had periodontitis. A long cone paralleling technique was used for periapical, or PA, images, and a paper sleeve with biting tab was employed for bitewing, or BW, images. A set of direct digital radiographs matching the conventional radiographs was taken for each subject under the same conditions. The distance from the cementoenamel junction to the interproximal alveolar crest on all readable surfaces was measured.

RESULTS

Examiners measured 857 PA image sites and 315 BW image sites matched on both radiographic systems. Paired t test showed significant differences in bone levels between the two systems. Measurements from conventional PA images were higher in all maxillary sextants (P < or = .02), and measurements from digital PA images were higher in mandibular anterior sextants (P = .007). Measurements in digital BW images were higher in mandibular posterior sextants (P = .002). A chi2 analysis of categorical bone levels (normal, early-to-moderate loss or advanced loss) showed significant differences between the imaging systems in revealing bone levels in both PA (P < .04) and BW (P < .001) images. Digital radiographs showed a higher number of sites with bone loss than did conventional radiographs.

CONCLUSIONS

Under normal clinical use, alveolar bone levels revealed on intraoral direct digital radiographs differ from those revealed on conventional radiographs.

CLINICAL IMPLICATIONS

Intraoral direct digital radiographs are not an equivalent substitute for conventional radiographs in evaluating alveolar bone levels.

Pulmonary nodule detection and visual search: P45 and P104 monochrome versus color monitor displays

RATIONALE AND OBJECTIVES

The faceplate of a cathode-ray tube (CRT) display monitor is covered on the vacuum side with a phosphor screen. The different phosphors that can be used for this screen have distinctly different physical properties that can affect the noise properties of the display. Differences in noise affect the signal-to-noise ratio and, hence, may affect diagnostic performance. This study evaluated observer performance and visual search parameters in the detection of pulmonary nodules, comparing two monochrome CRT monitors with different phosphors (P45 and P104) and a color CRT monitor.

MATERIALS AND METHODS

The receiver operating characteristic paradigm was used to evaluate observer performance with a series of radiographic chest images containing solitary pulmonary nodules. Eye position was recorded as the observers searched the images on each type of monitor.

RESULTS

Observer performance, as indicated by the area under the receiver operating characteristic curve and compared by means of an analysis of variance test, was best for the P45 monitor, next best for the P104 monitor, and worst for the color monitor. All differences were statistically significant. Eye-position parameters were also affected by monitor type. The time required to fixate the lesion and overall search times were longest with the color monitor.

CONCLUSION

The type of phosphor used in the CRT monitor faceplate can affect diagnostic performance and visual search parameters. Care should be taken in the selection of monitors for use in clinical radiology.